1. Technical Field
The present invention relates to a piezoelectric motor, a robot hand, a robot, a finger assist apparatus, an electronic component conveying apparatus, an electronic component inspecting apparatus, a liquid feeding pump, a printing apparatus, an electronic timepiece, and a projection apparatus.
2. Related Art
There is known a piezoelectric motor that vibrates a vibrating body including a piezoelectric material and drives a target object. The piezoelectric motor applies a fixed-cycle driving voltage to the vibrating body to thereby vibrate the vibrating body and drives a body to be driven with a projection provided on an end face of the vibrating body.
In the piezoelectric motor, there is also proposed a technique for forming four-divided electrodes on the surface of the vibrating body and switching an electrode applied with the driving voltage to thereby making it possible to switch a driving direction of the body to be driven (JP-A-2000-116162 (Patent Literature 1)).
However, in the proposed technique, since a switch needs to be used to switch the electrode applied with the driving voltage, first, a large current needs to be fed to drive the vibrating body. Therefore, a switch capable of switching the large current is necessary. The switch is increased in size or the piezoelectric motor including a circuit portion for switching an electric current is increased in size. Even when a switching element such as a power transistor is used, since the switching element capable of withstanding the large current cannot operate at high speed, at an instance of the switching, there is an instance when the driving voltage is not applied to all the electrodes. Therefore, the piezoelectric motor becomes uncontrollable at an instance when the driving direction is switched. It is difficult to perform delicate control.